Results 61 to 70 of about 971 (113)
For an arbitrary undirected graph G, we are designing a logical model for the Hamiltonian Cycle Problem (HCP), using tools of Boolean algebra only. The obtained model is a logic formulation of the conditions for the existence of the Hamiltonian cycle, and uses m Boolean variables, where m is the number of the edges of a graph.
Anatoly D. Plotnikov
wiley +1 more source
Structural Properties of Recursively Partitionable Graphs with Connectivity 2
A connected graph G is said to be arbitrarily partitionable (AP for short) if for every partition (n1, . . . , np) of |V (G)| there exists a partition (V1, . . . , Vp) of V (G) such that each Vi induces a connected subgraph of G on ni vertices.
Baudon Olivier+3 more
doaj +1 more source
Bounds for the smallest $k$-chromatic graphs of given girth [PDF]
Let $n_g(k)$ denote the smallest order of a $k$-chromatic graph of girth at least $g$. We consider the problem of determining $n_g(k)$ for small values of $k$ and $g$.
Geoffrey Exoo, Jan Goedgebeur
doaj +1 more source
The agreement distance of unrooted phylogenetic networks [PDF]
A rearrangement operation makes a small graph-theoretical change to a phylogenetic network to transform it into another one. For unrooted phylogenetic trees and networks, popular rearrangement operations are tree bisection and reconnection (TBR) and ...
Jonathan Klawitter
doaj +1 more source
Long cycles in certain graphs of large degree
Let G be a connected graph of order n and X = {x ∈ V : d(x) ≥ n/2}. Suppose |X| ≥ 3 and G satisfies the modified Fan′s condition. We show that the vertices of the block B of G containing X form a cycle. This generalizes a result of Fan. We also give an efficient algorithm to obtain such a cycle. The complexity of this algorithm is O(n2). In case G is 2‐
Pak-Ken Wong
wiley +1 more source
Algorithmic aspects of bipartite graphs
We generalize previous work done by Donald J. Rose and Robert E. Tarjan [2], who developed efficient algorithms for use on directed graphs. This paper considers an edge elimination process on bipartite graphs, presenting several theorems which lead to an algorithm for computing the minimal fill‐in of a given ordered graph.
Mihály Bakonyi, Erik M. Varness
wiley +1 more source
A Parametric Network Approach for Concepts Hierarchy Generation in Text Corpus
The article presents a preflow approach for the parametric maximum flow problem, derived from the rules of constructing concepts hierarchy in text corpus.
Sângeorzan L. S.+2 more
doaj +1 more source
Edge-Fault Tolerance of Hypercube-like Networks [PDF]
This paper considers a kind of generalized measure $\lambda_s^{(h)}$ of fault tolerance in a hypercube-like graph $G_n$ which contain several well-known interconnection networks such as hypercubes, varietal hypercubes, twisted cubes, crossed cubes and M\"
Li, Xiang-Jun, Xu, Jun-Ming
core
Path-induced closure operators on graphs for defining digital Jordan surfaces
Given a simple graph with the vertex set X, we discuss a closure operator on X induced by a set of paths with identical lengths in the graph. We introduce a certain set of paths of the same length in the 2-adjacency graph on the digital line ℤ and ...
Šlapal Josef
doaj +1 more source
The metric dimension and metric independence of a graph [PDF]
A vertex x of a graph G resolves two vertices u and v of G if the distance from x to u does not equal the distance from x to v. A set S of vertices of G is a resolving set for G if every two distinct vertices of G are resolved by some vertex of S. The
Currie, James, Oellerman, Ortrud R.
core